You have to understand skunk essence in the obvious it was designed to produce an odor to repel. It is a remarkable creation by God in being a thiol. It acts like alcohol in being airborne easily, but does not evaporate so is like an oil. In it's molecular chain it adheres to most organic and non organic matter, like a paint. The short version is you are attempting to make an apple fall up in defying the laws of nature in containing this secretion.
There are degrees of porousness to containers. Plastic, including lids breathe. As an example HIV penetrates latex in being smaller than the latex pores. Skunk essence is smaller than the pores on most things in nature, which is why it seeps through or it embeds in structures like hair or skin.
Using a syringe to extract uses porous plastic and non porous metal needles. The problem is the air as it is a carrier when transferring it to containers. Glass is the natural barrier in being non porous. The problem is the lid, as paper, plastic or rubber have larger pores than the essence.
The best solution is divide and conquer, meaning dispensing, by using glass trap lure 1 oz bottles, as their gaskets are meant to contain odors to a point. Garold Weiland who pioneered a number of methods, used to wax seal the tops of his Big Deuce which had skunk essence in it, and I still could smell it over time. What is required is placing the 1 oz bottles into a larger quart jar, with canning seals, and then a third gallon glass jar with a rubber seal.
In this you are dividing the scent with is escaping naturally by 3. The human nose can detect this scent in 10 parts per billion. 3 divisions and the scent is there, but you can not smell it.
In addition to this, humidity provides a carrier to your nasal membranes, so you should try for a drier air. Warm air also increases humidity, so cool air is preferred. A non working fridge makes a good 4th level to contain the odors.
Hope that helps solve your containment issue.